package myJava.io;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;

public class FileNIOTest {

	public static void main(String[] args) throws IOException {
		String src = "assets/io/File/BUILDING.txt";
		String dist = "assets/io/File/copyBUILDING.txt";
		fastCopy(src, dist);
	}

	public static void fastCopy(String src, String dist) throws IOException {
		/* 获得源文件的输入字节流 */
		FileInputStream fin = new FileInputStream(src);
		/* 获取输入字节流的文件通道 */
		FileChannel fcin = fin.getChannel();
		/* 获取目标文件的输出字节流 */
		FileOutputStream fout = new FileOutputStream(dist);
		/* 获取输出字节流的文件通道 */
		FileChannel fcout = fout.getChannel();
		/* 为缓冲区分配 1024 个字节 */
		ByteBuffer buffer = ByteBuffer.allocateDirect(1024);
		while (true) {
			/* 从输入通道中读取数据到缓冲区中 */
			int r = fcin.read(buffer);
			/* read() 返回 -1 表示 EOF */
			if (r == -1) {
				break;
			}
			/* 切换读写 */
			buffer.flip();
			/* 把缓冲区的内容写入输出文件中 */
			fcout.write(buffer);
			/* 清空缓冲区 */
			buffer.clear();
		}
	}

}
